fix loading stale Primer Brand stylesheet in Doctocat (#1115)

Author: rezrah

apps/next-docs/package.json

@@ -31,7 +31,7 @@
     "start": "next start"
   },
   "dependencies": {
-    "@primer/doctocat-nextjs": "0.5.8",
+    "@primer/doctocat-nextjs": "0.6.0",
     "@primer/octicons-react": "19.15.1",
     "next": "15.2.4",
     "react": ">=17 <= 18",